Shazam is the alter ego of Billy Batson, who works as a radio news reporter and was chosen to be a champion of good by an ancient wizard (also named Shazam). Whenever Billy speaks the word "Shazam!", he is struck by a magic lightning bolt that transforms him into an adult superhero empowered with the abilities of six archetypal, historical figures. Several friends and family members, most notably Marvel Family cohorts Mary Marvel and Captain Marvel Jr. can share Billy's power and become "Marvels" themselves.
Hailed as "the world's mightiest mortal" in his adventures, Captain Marvel was nicknamed "The Big Red Cheese" by arch-villain Doctor Sivana, an epithet later adopted by Captain Marvel's fans. Based on sales, Captain Marvel was the most popular superhero of the 1940s. His Captain Marvel Adventures comic book series sold more copies than Superman and other competing books of the time. Captain Marvel was also the first comic book superhero to be adapted into film, in a 1941 Republic Pictures serial titled Adventures of Captain Marvel.
Fawcett ceased publishing Captain Marvel-related comics in 1953, partly because of a copyright infringement suit from DC Comics, alleging that Captain Marvel was a copy of Superman. In 1972, DC licensed the Marvel Family characters and returned them to publication, acquiring all rights to the characters by 1991. DC has since integrated Captain Marvel and the Marvel Family into their DC Universe, and have attempted to revive the property several times with mixed success.